the save-summary trick is handy. when you've used it in other stories, did the characters still feel like themselves in the new chat, or did you have to remind the GM how they act?
The one other story I did it for it kept the characters quite well for the key characters, and then some of the minor characters deviated somewhat. But that one did have a lot of characters and spanned a quite long "in-game" time. For Galatea, the story is quite tightly scripted, with few characters, so I would think it wouldn't be too noticeable.
In summary, I think it depends on how much the game book defines and describes the characters, the overall tone of the story, as well as how the save summary is written. You could also consider instructing the GM/AI specifically to focus on retaining the feel of the characters in the save game OCC.